TRI-CONE BITS FOR HORIZONTAL AND HARD FORMATION DRILLING APPLICATIONS

摘要

The present invention discloses a tri-cone drill bit comprising: three headsectionswith upper parts thereof jointed together to form a bit body, three conesrotatablelymounted to lower ends of the head sections respectively, nozzle socketsdesigned onthe bit body between respective head sections and each having a hole in whichanozzle is mounted, wherein gage cutters are mounted to an upper trailing sideof eachhead O.D. surface to form a gage holding surface thereon, and a leading sideof eachhead section is backwardly slanted as a whole. The design of gage surface attrailingsides of head sections increases the bit's stability, reduces lateralvibration and alsoreduces tendency of bit deflection in horizontal drilling applications andeffectiveworking life of the bit is improved. Backward slant of leading sides of headsectionsfacilitates upward carrying of drilling cuttings and improves drillingefficiency. Jetsfrom the nozzles are respectively directed to the leading side of eachfollowing cone,which enhances bottom hole cleaning and cooling of cutting elements and leadsto alonger working life and higher ROP of the bit.